<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
         .out{
             width: 300px;
             height: 200px;
             border:1px red solid;
             margin: 0px auto;
         }
         .div_top{
             width: 100%;
             height: 50px;
             border-bottom: 1px red  solid;
             display: flex;

         }
         .login{
             width: 260px;
             height: 100%; 
             text-align: center;
             line-height: 50px;
             /* border: 1px red solid;  */
            }
            .showclose{
                width: 40px;
                height: 50px;
                text-align: center;
                line-height: 50px;
                color:red;
            }


    </style>
</head>
<body>

     <button>登录</button>
    
     <div class='out'>
        <div class='div_top'>
            <div class='login'>登录界面</div>
            <div class='showclose'>X</div>
        </div>
        <div class='div_input'></div>
    </div>


</body>
</html>